Successful motion control and measurement integration highly depends on using the right hardware components working together in a single software environment. For high performance integration applications, the new NI PXI-7350 8-axis motion controller (found at www.ni.com/motion) combined with LabVIEW 7 Express offers a variety of very powerful features for creating both simple and high performance motion and measurement applications.
Onboard Data Acquisition for Simple Measurements
A variety of applications often require both motion control and some type of analog I/O to make simple measurements. Using the PXI-7350, you now have eight 16-bit analog inputs to get accurate, single point, software-timed data acquisition. This onboard data acquisition works well for basic measurements, such as temperature, that do not require hardware-timed acquisition. Using these analog inputs you could read potentiometers for position measurements, load cells, and other sensors.
You could also use the analog inputs to provide feedback to motion control systems. For example, analog feedback is useful for applications such as lifecycle testing of a button where an actuator pushes a button at a given torque repeatedly. In this example, an encoder may not provide all of the necessary information to know the torque. The PXI-7350 enables you to use an analog force sensor as primary feedback to the motion system. This ensures that you press the button with the correct amount of load each time, making the test consistent.
High-Speed Position Triggering
Although software-timed data acquisition may work for a variety of cases, some applications, such as vibration testing commonly used for machine monitoring, require something more powerful.
Arbitrary position triggers on the PXI-7350 enable you to trigger measurements as you reach arbitrary, pre-determined positions in your system at rates of up to 2 kHz, more than a 100% increase over previous motion controllers. You can use this functionality if you know that you are going to need a measurement at a certain position within your system.
When triggering at a set position interval, you can trigger at even higher rates of 4 MHz using the periodic position triggers. Periodic position triggers are useful in applications like a surface scanning system. Triggering a single point measurement at each position correlates each measurement with a position and produces an accurate profile of the scan.
Along with position triggering, the advanced triggering functionality available with PXI enables you to send signals for position triggers and position captures all through the backplane of the PXI chassis. This makes integrating the motion controller and data acquisition boards very easy by simply routing all of your trigger signals using LabVIEW without any special cables or external wiring.
The new PXI-7350 8-axis motion controller provides a host of new features to enable you to create powerful, synchronized motion control and measurement applications. Combined with LabVIEW, it helps you develop both basic and high performance integrated applications to meet your automation needs.